Radio receiving device



5W a g I l l i F J'M'WF $7) WW I e y E 5 2 44W l l l l MM June 30, 1925. 11,544,157

I c. F. JENKINS RADIO RECEIVING DEVICE Filed Sept. 11, 1922 Patented June 30, 1 925.

" UNITED STATES PATENT OFFICE.

CHARLES FRANCIS JENKINS, OF WASHINGTON, DISTRICT OF COLUMBIA, ZASSIGNOR TO JENKINS LABORATORIES, OF WASHINGTON, DISTRICT OF COLUMBIA, A COR- PORATION.

Application filed September 1 '0 all whom it may concern:

Be it known that I, CHARLES FRANCIS JENKINS, a citizen of the United States, and resident of WVashi'ngton, in the District of Columbia, have invented certain new and useful Improvements in Radio Receiving Devices, of which the following is a specification, reference being had therein to the accompanying drawing.

The invention relates to transmitting pictures by radio-energy and an object is to change automatically the intensity of light produced causing it to fluctuate in accordance with predetermined conditions.

In my application Serial No. 543,331, I provide for changing the applied value of a light source of fixed intensity so that it may better reproduce, at a distant station, a picture or the like.

In this present case, I provide that current fluctuations at the sending station shall create like fluctuations in the intensity of the light source at the receiving station.

In the accompanying drawings, which show the apparatus only diagrammatically, Fig. 1 shows the sending station circuits, and "Fig. 2 indicates receiving station circuits.

In these figures, A, A are amplifyingtubes, and B, B detector and amplifying tubes. C designates a photo-electric cell of approved character, D a circuit breaker, and E an incandescent lamp.

Any fluctuating light falling upon the cell C at the sending station causes a change in grid potential at the tube A, changing the amplified current in the plate circuit which includes the interrupter D,

RADIO RECEIVING DEVICE.

11, 1922. Serial No. 587,506.

The fluctuating light falling on the cell C creates a fluctuating current which is broadcasted in the usual way by antenna: and picked up by other antennae, and when amplified is impressed on the circuit containing the lamp E. This latter circuit contains batteries capable only of keeping the lamp filament at a dull glow, while, with the radio current added, the lamp takes on incandeseence which fluctuates exactly as the radio current fluctuates but it is of course the photographic value, not the illumination \value, which is here important. Since the light at the cell and the light at the receiving station fluctuate in exactly the same way, if light from different parts of a picture falls in succession upon the cell, and if the like-fluctuating light at. the receiving station be synchronously passed over a sensitized photographic plate, a duplicate of the picture at the sending station will be produced at the receiving station.

For obtaining extreme sensitivene'ss' of the light to current fluctuations, the cell may be filled with hydrogen or other gas which readily conducts heat, and further, the gas may be,under compression.

What I claim is-- In an apparatus for receiving radio waves, the combination of an electron tube, an output circuit therefor, an electric light connected directly in said output circuit, said light being maintained normally at a dull glow when no signals are being received.

In testimony whereof I hereunto aflix my signature.

CHARLES FRANCIS JENKINS. 

